>>9973733The simplest thing to do is just to watch his website. Check it every morning, because sometimes he updates without saying anything. Generally, he'll post about it on instagram the day of or before a release. He often releases several figures at once. Rampage toys has a partnership with Karz to release SHB figures with their own heads. In fact there's one in his shop right now (
https://rampagetoysandart.bigcartel.com/product/akamatsu-1-off-shb-figure)
In terms of secondary market, Yahoo auctions (through proxy buyers. I use From Japan), Mandarake, Japanese Mercari, Ebay, Facebook groups, etc. Instagram resellers also. I got a good chunk of my collection in a single bulk buy from a guy on instagram. I follow the tag "Sofubi for sale". A word of warning about ebay listings though: You will often find the exact same listing on yahoo auctions for 100 or more bucks cheaper.
Example:
https://www.fromjapan.co.jp/en/auction/yahoo/input/g1054395782/lgk-link_top_searchand
https://www.ebay.com/itm/354169545409?hash=item52762662c1:g:t3cAAOSwVEVi0pE~Not sure if this is the work of some shitty middle man wanna be drop shipper or what. But Mandarake also has an ebay page so watch out for overpaying by buying their stuff listed there.
>>9975118https://order.mandarake.co.jp/order/listPage/list?page=2&categoryCode=020112&lang=enMandarake holds its sofubi under two places (generally) and they are Sofubi AND artist toys. Sofubi includes mass produced stuff while artist toys is the smaller scale stuff we tend to focus on.
>>9975503RxH figures are often not too hard to get your hands on if you don't mind grabbing the less popular molds or colorways. People aren't as big a fan of that body, for example, compared to the larger one. Makes it cheaper.